Found in innumerable consumer products such as non-stick coatings and stain-resistant fabrics, as well as in military grade firefighting foams, per- and polyfluoroalkyl substances (PFASs) can be dangerous if they leach into drinking water. They do not easily break down in the human body, and can accumulate over time to dangerous levels.
For this reason, the Environmental Protection Agency (EPA) has set a PFAS limit of 70 ppt (parts per trillion) in drinking water. Yet the most common PFASs, PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonic acid) have been detected in over 100 public drinking water systems across 33 states. Until now, it was difficult for municipalities to get these levels under control.